UPPSALA, SWEDEN —Nocturnal gastroesophageal reflux (GER) is strongly associated with asthma and respiratory symptoms, a large European study has shown.[1] The study found a twofold to threefold rise in the odds of asthma-like symptoms and asthma among subjects who reported having GER symptoms (heartburn and belching) after bedtime at least one or two times a week.

“We have no doubt that reflux causes asthma,” Christer Janson, MD, one of the principal investigators, said in an interview with PULMONARY REVIEWS. “However, we are not sure if reflux-related asthma is different from asthma due to allergies or the other usual causes.”

The study found a strong relationship between nocturnal GER and sleep-disordered breathing symptoms such as snoring, apnea, and daytime sleepiness, he also reported. Dr. Janson is an Associate Professor in the Department of Medical Sciences, Respiratory Medicine, and Allergology at Uppsala University in Sweden.

GENERAL POPULATION SURVEYED

Of the 2,661 adults studied, 2,202 were a random sample from the general population. The rest were invited to participate specifically because they had reported asthma attacks, nocturnal breathlessness, or current asthma medication use.

All participants were asked about respiratory symptoms and diseases, medication use, and environmental factors for respiratory disease, and they all completed a questionnaire about sleep quality during the past few months. Most also underwent lung function and allergy tests.

THE GER/ASTHMA LINK

One hundred one (4.6%) of the randomly selected subjects reported nocturnal GER. Compared to those without GER, these subjects had adjusted odds ratios of 1.7 to 3.0 for wheeze; nocturnal chest tightness, breathlessness, and cough; breathlessness during activity and at rest; physician-diagnosed asthma; and morning phlegm production.

They were also more likely to have a body mass index (BMI) indicating that they were overweight and to report sleep-disordered breathing. They demonstrated greater peak flow variability, as well.

The total number of patients identified as having asthma among both samples (the randomly selected subjects and those reporting symptoms) was 276. Among these patients, nocturnal GER was again associated with greater peak flow variability, as well as a significantly higher BMI and incidence of nocturnal cough, morning phlegm production, and several sleep-disordered breathing symptoms.

It is unknown how GER might cause asthma, but Dr. Janson suggested microaspiration—the inhalation of small amounts of gastric acid. He advised asking all patients with asthma about GER symptoms.

Antireflux therapy is reasonable for asthma patients with GER, he said, although he acknowledged that proof that it will improve lung function is lacking; a three-month trial of a high-dose proton pump inhibitor has been recommended. For asthma patients with nocturnal GER and sleep-disordered breathing, the possibility of sleep studies and a trial of continuous positive airway pressure should be considered.

—Timothy Begany

Reference
1. Gislason T, Janson C, Vermeire P, et al. Respiratory symptoms and nocturnal gastroesophageal reflux: a population-based study of young adults in three European countries. Chest. 2002;121:158-163.

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